1. Field of Invention
The present invention relates generally to medical devices. More particularly, the present invention relates to trigger controlled surgical instruments.
2. Description of Prior Art
Handles for surgical instruments have traditionally been based on a paradigm of design that is decades old, a design that was adopted to facilitate their use in upper airway endoscopy. These instruments are bent such that their handles are as much as 90 degrees out of alignment with their functional ends. The original design was required to allow a user to have a direct line of vision down a sheath into the area where the surgery is performed. With the advent of fiber optics, the requirements for the bent handle design were eliminated. Surgeons today manipulate surgical instruments by means of a video screen, not a direct line of vision down a sheath. Given this change in technology regarding the visual aspects of surgery, it is surprising that the handles of a majority of surgical instruments have remained unchanged.
Surgical instruments with this bent-handle design can be troublesome to use. They require a user to hold their wrist awkwardly for long periods of time, in a position that encourages the development of Carpal Tunnel Syndrome and chronic joint stress. Many users have taken to holding the instruments in a manner not consistent with their design in an attempt to alleviate the pain and fatigue of long procedures.
Additionally, the bent-handle design does not efficiently translate force from the handle to the functional end of the instrument. Force applied to the handle of the instrument is translated to the functional end to perform the desired action. If the handle is bent out of line with the longitudinal axis of the functional end, a portion of the applied force will be translated to movement of the instrument in a direction that is essentially perpendicular to this axis. This undesirable movement may be translated along the instrument to the functional end, thus compromising stability.
In addition to the inefficient translation of force from the handle to the functional end of the instrument, the bent-handle design better facilitates surgeon use of the tool as a functional extension of a users hand.